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APPENDIX

ammonia (and in some cases hydroxylamine), the primary nitro-
paraffins arc not hydrolysed by potash, but dissolve, forming
the soluble potassium salt, and on reduction give the primary
ami no,

CJ1;,N(X i- 3IL = QjIIgNILj + 2lI30.

Amyl nitrite is tised in the preparation of dia/o-salts (see Prep.
62, p. 161).

PRKl'A RATION   IO.

Acetyl Chloride.-- Either PC1;{ or PCI- are almost in-
variably used in the preparation of acid chlorides. In the case
of PCI- only a. portion of the chlorine of the reagent is utilised
(see Prep. 98, p. 208), POC1:J being produced in the reaction,
The use of one or other reagent is determined by the nature of
the product. If the latter has a low boiling-point the trichloride
is preferred, if a high boiling-point, the pentachloride may be
used and the oxychloride expelled by distilling /// vacua from a
water-bath (see Prep. 16, p. 85). The pentachloride is more
frequently used in the preparation of aromatic acid chlorides,
hut there arc occasions, which experience can only determine,
when the trichloride is preferable.

Phosphorus oxychloride and the sodium salt of the acid can
also be used.

2(:ii:,.(.:(K)Nji i poci3 -2rn.,coci + NUPO,, -i- NuCi.

Also thionyl chloride, SOC1,,, may often be used with advan-
tage in place of the chlorides of phosphorus,

I + SOCL -C

Acid chlorides react with alcohols and phenols, and in general
with substances containing a "hydroxyl " (OH) group. Acid
anhydrides have a similar behaviour, and both substances may
be used in determining the number of such groups in a
compound. Thus glycerol forms a triacctyl derivative, whilst
glucose yields a pentacetyl compound. By hydrolysing the
acetyl derivative with alkali, and then estimating the amount of
alkali nt'iilralised by titralion, the number of acetyl groups can
be estimated (see p. 222).
The presence of the "aniino" (NTL) group is determined by
a similar reaction.
The synthesis of aromatic ketones may be effected with the
CO HUN'S ADV. P. O. C                                                                 R